1. Field of the Invention
The present invention relates to improving ruminant animal performance by increasing the postruminal availability of supplemental dietary choline to such animals. More specifically it relates to a method for improving ruminant animal growth, feed conversion and carcass quality by increasing the availability of supplemental dietary choline to animals with a developed rumen. This is achieved by co-administering choline with a propionate-enhancing antibiotic compound.
2. Prior Art
While choline supplementation of nonruminant diets has proved very effective for enhancing animal performance and is now widely accepted in the animal husbandry industry, direct supplementation of ruminant diets with choline is not currently practiced. This is because there has not been a clear indication that dietary supplementation with choline or choline compounds of any kind would be efficacious. This position is based in large part on research into the disposition of dietary choline in the rumen, both in vivo and in vitro, which indicates choline is rapidly catabolized to trimethylamine, acetate, ethanol or ethylene glycol, none of which are biologically active substitutes for choline itself. See Neill, Alan R. et al, Biochem. J. (1978) 170, 529-535).
Some field studies indicate choline or choline salts alone improve one or more performance parameters in ruminant animals. See Dwyer, I. A., Animal Nutrition and Health, October, 1969 and Fromsee, T. S., and R. Oltjen, 1975, J. Animal Sci., 41:416. However, beneficial responses were not observed in other studies. See Harris, R. R., H. F. Eates and J. E. Barrett, Jr., 1966, J. Animal Sci. 25:248 and Weis, M. B., D. N. Blumer and E. R. Barrick, 1964, North Carolina Agr. Exp. Sta. Ans. Report 139, A. . Series 10 22). Ruminant dietary supplementation with choline fatty acid complexes, for example, choline stearate, has been claimed, in U.S. Pat. No. 3,873,719, to improve weight gain and/or quality of meat in ruminates while maintaining or improving feed conversion. However, the supplementation of meat producing ruminant diets with choline in any form is not currently a common practice.
There is no known art which indicates propionate-enhancing antibiotics will enhance the availability of choline in ruminant diets. A review of the activity of the propionate-enhancing polyether ionophore nigericin indicates it decreases mitochondrial oxidation of choline. See: Antibiotics I: Mechanism of Action, Ed D. Gottlieb and P. D. Shaw, Springer-Verlag New York, Inc., 1967, pp. 613-616. Inhibition of rumen fluid amino acid degradation by various antimicrobials, including a propionate-enhancing polyether ionophores, is noted in Schelling, G. T., et al, Fed. Proc. 37:411 (abstr.) 1978 and Chalupa, W., W. Corbett and J. R. Brethour, J. Animal Sci., 51:70, 1980.
Several U.S. patents, for example, U.S. Pat. Nos. 4,100,171, 3,790,668 and 3,927,836, claiming propionate-enchancing compounds disclose the use of surfactants, including lecithin, for preparing suspensions of water-insoluble forms of these compounds. None of these several patents disclose or intimate that co-administration of such antibiotics with a diet-supplementing amount of choline or choline containing compounds will affect the availability of choline to ruminant animals.